初至拟合静校正法在独山子探区的应用

Application of First Break Fitting Static Correction Method to Dushanzi Area in Southern Margin of Junggar Basin

准噶尔盆地南缘独山子探区表层地质结构复杂,野外静校正很困难。常规模型静校正方法由于受自身假设条件的限制,难以满足实际复杂结构模型的精确描述而导致静校正量的偏差。初至拟合静校正法避免了复杂的近地表模型建立过程,以简单表层结构初至旅行时所呈现的线性渐变规律作为静校正量求解的目标。只考虑初至时间的变化,不考虑引起初至时间变化的原因。通过初至拟合的方法实现初至时间线性渐变规律的校正,将校正的初至时间分解到相应的炮检点,以达到基准面静校正的目的。该方法在准噶尔盆地南缘独山子复杂地表区的应用取得了良好的效果。

Dushanzi prospecting area in southern margin of Junggar basin is characterized by complex surface structures, which makes the field static correction very＂ difficult. And using conventional model-based static correction methods are heyond accurate description of tire leal complex structural models due to restrictions of various assumptions of the methods, normally resulting in deviation of static correction values. This paper presents a new method for the static correction, by which the process of complex surface modeling can be got rid of. It takes the linear gradual change law appeared in first break travel time of simple surface structure as the target for solving the static corrections by only considering the change of first break time rather than its cause, and makes the correction of linear law of first break time by breaking down the corrected first break time into relevant shots and receivers so as to reach the purpose of datum static correction. The case study of Dushanzi area shows that better results have been gained using this method.